System, method and quantum computer for manipulating a spin qubit

Abstract

The application discloses a spin quantum bit control system, a method and a quantum computer. The spin quantum bit control system is used for controlling a spin quantum bit on a semiconductor quantum processor, and comprises: an upper computer module configured to receive a quantum computing task and issue a corresponding task instruction; wherein the task instruction comprises a waveform coefficient of a pulse signal; an instruction processing module configured to generate and output waveform data of the pulse signal waveform according to the waveform coefficient; and a signal generation module configured to output a corresponding pulse signal according to the waveform data. The application generates waveform data of a pulse signal by using a waveform coefficient, can solve the problem that a large amount of waveform data of a pulse signal occupies memory and slow transmission affects the computing efficiency of quantum computing, and can greatly improve the computing efficiency of quantum computing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum computing, and particularly to a spin qubit control system and method and a quantum computer. BACKGROUND

[0002] A quantum chip is a core component for running quantum computing, and a plurality of qubits are integrated on the quantum chip, such as spin qubits on a semiconductor quantum chip. A direct current signal and a pulse signal are used to control the spin qubits, and a radio frequency signal is used to measure the spin qubits.

[0003] When a pulse signal is used to control a two-qubit gate of a spin qubit, the precision of the pulse signal is required to be very high, usually in nanoseconds, for example, a waveform with a pulse period less than 100 ns. In addition, the pulse signal corresponding to the two-qubit gate control is various, and the pulse amplitude and pulse period of each pulse signal are different, which need to be determined according to the quantum computing task to be executed. It can be imagined that in a quantum computing task, a plurality of different high-precision pulse signals need to be applied to the spin qubits, and in order to ensure the accuracy of the quantum computing task, the control is usually repeated several thousand or even tens of thousands of times, and the time interval of the repeated operation is also different. Specifically, all the pulse signals of the control are combined into a combined pulse signal and applied to the spin qubits, and the control result is measured.

[0004] In the prior art, an upper computer usually receives a quantum computing task, determines the waveform of the pulse signal to be applied to each spin qubit according to the quantum computing task, and downloads the waveform data to a lower computer for storage in the lower computer. The lower computer outputs the corresponding pulse signal according to the waveform data; wherein the lower computer usually uses a quantum control system. As described above, the pulse signals for controlling the qubits are various, and the waveform parameters of each pulse signal are also different, and each waveform parameter needs to be downloaded. Moreover, some waveforms are combined pulse signals, and the data volume of the waveform is very large, which takes a lot of time to download and occupies a lot of memory when stored in the quantum control system.

[0005] In addition, this waveform data is pre-stored and cannot be adjusted in real time. When the pulse signal needs to be adjusted, the upper computer needs to update the waveform data of the pulse signal and re-download it to the lower computer, which directly reduces the computing efficiency of quantum computing due to the time of data download. SUMMARY

[0006] The purpose of the present application is to provide a spin qubit control system and method and a quantum computer to solve the problem of large waveform data volume of pulse signals in the prior art, which occupies memory and slows down the transmission and affects the computing efficiency of quantum computing, and to greatly improve the computing efficiency of quantum computing.

[0007] To solve the above technical problems, the application provides a spin qubit control system for controlling spin qubits on a semiconductor quantum processor, comprising:

[0008] A host computer module is configured to receive a quantum computing task and issue a corresponding task instruction; wherein the task instruction comprises a waveform coefficient of a pulse signal;

[0009] An instruction processing module is configured to generate and output waveform data of the pulse signal waveform according to the waveform coefficient;

[0010] A signal generation module is configured to output a corresponding pulse signal according to the waveform data.

[0011] The spin qubit control system described above, preferably, the instruction processing module outputs each waveform data according to a working clock frequency.

[0012] The spin qubit control system described above, preferably, the number of waveform data output by the instruction processing module per clock cycle is equal to the quotient of the sampling rate of the signal generation module and the working clock frequency of the instruction processing module.

[0013] The spin qubit control system described above, preferably, the waveform coefficient comprises a starting amplitude of a rising edge of a pulse signal waveform, an amplitude increment, and a total amount of waveform data.

[0014] The spin qubit control system described above, preferably, the instruction processing module comprises:

[0015] A state starting unit is configured to send an output request according to the task instruction;

[0016] A data conversion unit is configured to call the task instruction and output corresponding waveform data in response to the output request;

[0017] A data judgment unit is configured to determine whether additional sampling point data is needed according to the total amount of waveform data of the waveform data of the rising edge and the number of waveform data output per clock cycle; wherein the total amount is the total amount of waveform data of the rising edge of the pulse signal waveform.

[0018] The spin qubit control system described above, preferably, when the quotient of the total amount of waveform data of the waveform data of the rising edge and the number of waveform data output per clock cycle is an integer, the data judgment unit determines no and directly outputs the waveform data.

[0019] The spin qubit manipulation system as described above, preferably, when the quotient of the total amount of waveform data of the rising edge and the number of waveform data output per clock cycle contains a remainder, the remainder is padded to the number of waveform data output per clock cycle, and the padded waveform data is output.

[0020] The spin qubit manipulation system as described above, preferably, further comprises a storage module for storing the task instructions and forwarding to the data conversion unit.

[0021] The spin qubit manipulation system as described above, preferably, the instruction processing module is a functional module integrated in the FPGA.

[0022] Another aspect of the present application provides a spin qubit manipulation method for manipulating spin qubits on a semiconductor quantum processor, comprising:

[0023] Receiving a quantum computing task and issuing corresponding task instructions; wherein the task instructions include waveform coefficients of pulse signals;

[0024] Generating and outputting waveform data of the pulse signal waveform according to the waveform coefficients;

[0025] Outputting corresponding pulse signals according to the waveform data.

[0026] Still another aspect of the present application provides a quantum computer comprising any one of the above spin qubit manipulation systems or using the above manipulation method to manipulate spin qubits.

[0027] Compared with the prior art, the spin qubit manipulation system provided by the present application is used for manipulating spin qubits on a semiconductor quantum processor, and receives a quantum computing task through a host computer module and converts it into corresponding task instructions for issuing. The task instructions include waveform coefficients of pulse signals, and through an instruction processing module, waveform data of a complete waveform of the pulse signal is generated and output according to the waveform coefficients in the task instructions. Then, through a signal generation module, corresponding pulse signals are output according to the waveform data. The waveform coefficients of the pulse signals have a smaller data volume than the complete waveform data of the pulse signals, and are easy to transmit and store. The host computer of the present application only needs to send task instructions including the waveform coefficients of the pulse signals, and the instruction processing module of the lower computer generates complete waveform data of the pulse signals and outputs them according to the waveform coefficients. When the pulse signals need to be adjusted, the host computer updates the waveform coefficients and issues them, and the instruction processing module generates corresponding waveform data and outputs them according to the updated waveform coefficients, which greatly improves the efficiency of quantum computing.

[0028] The spin qubit manipulation method and the quantum computer provided by the application belong to the same application concept as the spin qubit manipulation system, and therefore have the same beneficial effects, which will not be described here again. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A schematic diagram of a combined pulse waveform provided by an embodiment of the application;

[0030] Figure 2 A schematic diagram of a spin qubit manipulation system provided by an embodiment of the application;

[0031] Figure 3 A schematic diagram of an instruction processing module provided by an embodiment of the application;

[0032] Figure 4 A flowchart of a spin qubit manipulation method provided by an embodiment of the application. BRIEF DESCRIPTION OF DRAWINGS

[0034] 10 - host computer module, 20 - instruction processing module, 30 - signal generation module;

[0035] 210 - state starting unit, 220 - data conversion unit, 230 - data judging unit. DETAILED DESCRIPTION

[0036] The specific embodiments of the application will be described in more detail below with reference to the accompanying drawings. The advantages and features of the application will be more apparent from the following description and claims. It should be noted that the drawings are very simplified and use non-precise proportions, only to facilitate, clarify the purpose of assisting the description of the embodiments of the application.

[0037] In the description of the application, it should be understood that the terms "center", "upper", "lower", "left", "right", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0038] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0039] In a semiconductor quantum computer, multiple spin qubits are integrated on a quantum processor, usually, a direct current signal is applied to the quantum processor to form a spin qubit, and a pulse signal is used to control two adjacent spin qubits, so that a two-qubit gate operation can be performed between the two spin qubits. The fidelity of the two-qubit gate operation is closely related to the pulse response time of the applied pulse signal, and the rising edge and falling edge of the applied pulse signal are required to be very short, usually in nanoseconds.

[0040] The pulse signal is usually output by a signal source, a signal generator, or a quantum control system, and the waveform parameters of the pulse signal depend on the quantum computing task to be performed, which is usually issued by a host computer. When a spin qubit performs a complex quantum computing task, several pulse signals with different signal parameters need to be continuously applied to the same spin qubit. When repeated control is required, the same pulse signal needs to be continuously applied to the same spin qubit. Whether the signal parameters of the pulse signal are the same or not, for several pulse signals, the waveforms of the several pulse signals are usually spliced into a combined pulse waveform in the host computer, and the combined pulse waveform is issued to the quantum control system.

[0041] As shown in a combined pulse waveform, Figure 1 The horizontal axis of the coordinate represents the pulse time, and the vertical axis represents the pulse amplitude. The combined pulse waveform in the figure includes several pulse signals with different pulse amplitudes and pulse times, and the time intervals between the pulse signals are also different. It can be imagined that the complexity of the combined pulse waveform is very high. Among them, each pulse signal has similarities, that is, the pulse response time of the rising edge and the falling edge is very short, and the slope is very steep. For the combined pulse waveform, the host computer needs to issue all the waveform data of the combined pulse waveform to the quantum control system. It can be imagined that the complexity and quantity of the issued waveform data are very large. Moreover, when one pulse waveform in the combined pulse waveform needs to be optimized, the pulse waveform needs to be updated and the updated combined pulse waveform needs to be reissued, which greatly affects the efficiency of quantum computing.

[0042] It should be noted that the combined pulse waveform Figure 1 of the example is only an example, and the specific parameters and waveform data of the applied single pulse signal and the combined pulse waveform need to be determined according to the quantum computing task to be performed, which will not be described in detail in this embodiment.

[0043] As Figure 2As shown, the embodiment of the present application provides a spin quantum bit control system for controlling spin quantum bits on a semiconductor quantum processor, comprising: a host computer module 10 for receiving a quantum computing task and issuing a corresponding task instruction; wherein the task instruction comprises a waveform coefficient of a pulse signal; an instruction processing module 20 for generating and outputting waveform data of the pulse signal waveform according to the waveform coefficient; and a signal generation module 30 for outputting a corresponding pulse signal according to the waveform data.

[0044] Specifically, the host computer module 10 can include a functional module integrated in a classical computer for receiving a quantum computing task initiated by a user and analyzing the quantum computing task to obtain a corresponding task instruction, wherein the task instruction is used to control the quantum control system to output a plurality of pulse control signals to the spin quantum bits for executing a specific quantum computing task. The instruction processing module 20 and the signal generation module 30 are functional modules integrated in a lower computer and are in communication connection with the host computer module 10.

[0045] The waveform of the pulse signal generally includes square wave, triangular wave, rectangular wave, trapezoidal wave, etc. The task instruction includes parameters of each pulse signal to be output, and the parameters only include waveform coefficients of various waveforms and do not include all waveform parameters of the pulse signal, such as corresponding time and amplitude parameters. The waveform data of the pulse signal can generally be in the form of a function expression, for example, the rising edge or falling edge of the pulse signal can be expressed in the form of a linear function. For a function expression, the coefficients therein can be determined, i.e., the corresponding output value can be obtained according to different input values. The waveform coefficient is the same as the coefficient of the function expression, and after the waveform coefficient is determined, the amplitude increment of the rising edge and the falling edge of the pulse signal can be determined, and the corresponding waveform coefficient can be issued for the pulse signal with different amplitude increments; when a given initial value and a termination value are given, the waveform parameters of the entire pulse signal can be determined.

[0046] As described above, the host computer issues the waveform coefficient in the form of a task instruction to the instruction processing module 20, and in combination with the amplitude required by the spin quantum bit executing different quantum computing tasks, and the instruction processing module 20 determines the complete waveform data of the pulse signal, and then the signal generation module 30 outputs the corresponding pulse signal according to the waveform data, which greatly reduces the amount of data sent by the host computer module 10 and improves the efficiency of quantum computing.

[0047] It's worth noting that, taking a trapezoidal waveform pulse signal as an example, it includes a rising edge, a falling edge, and a high-level state. The amplitude increments of the rising and falling edges are in opposite directions. For a trapezoidal waveform, the task instruction only needs to include the waveform coefficient for the rising edge. Furthermore, the low-level and high-level amplitudes of the waveform are fixed, and each waveform coefficient corresponds to a trapezoidal waveform pulse signal. It's conceivable that the data volume of the waveform coefficients is very small, making it very convenient for the host computer to send without consuming much memory. Moreover, when the pulse signal needs adjustment, only the sent waveform coefficients need to be adjusted, which helps improve the efficiency of quantum computing.

[0048] In addition, the waveform data generated by the instruction processing module 20 based on the waveform coefficients needs to be sampled according to the sampling rate of the signal generation module 30, and the sampled waveform data is output to the signal generation module 30, which then outputs the corresponding pulse signal.

[0049] In this embodiment, the instruction processing module 20 has a clock operating frequency, and the instruction processing module 20 outputs the waveform data according to the operating clock frequency. That is, in each cycle of the operating clock signal, the instruction processing module 20 outputs a certain number of waveform data to the signal generation module 30. For example, the operating clock frequency of the instruction processing module 20 is 100MHz.

[0050] Furthermore, when the instruction processing module 20 outputs waveform data to the signal generation module 30, the number of waveform data output by the instruction processing module 20 per clock cycle is equal to the quotient of the sampling rate of the signal generation module 30 and the operating clock frequency of the instruction processing module 20. For example, if the sampling rate of the signal generation module 30 is 1 GHz and the operating clock frequency of the instruction processing module 20 is 100 MHz, then the instruction processing module 20 needs to output 10 waveform data points per clock cycle as sampling points for the signal generation module 30. This is to match the number of sampling points of the instruction processing module 20 and the signal generation module 30, ensuring the accuracy of the pulse signal output by the signal generation module 30.

[0051] The instruction processing module 20 generates complete waveform data of the pulse signal based on the waveform coefficients sent by the host computer. In this embodiment, the waveform coefficients include the amplitude increments and initial amplitudes of the rising and falling edges of the pulse signal waveform. Specifically, for the pulse waveform of a pulse signal, the amplitude increments of the rising and falling edges are opposite; the initial amplitude of the rising edge is the same as the final amplitude of the falling edge, and the final amplitude of the rising edge is the same as the initial amplitude of the falling edge. For the instruction processing module 20, once the amplitude increments and initial amplitudes of the rising or falling edge are determined, the complete waveform data of the pulse signal can be determined.

[0052] Furthermore, the operating clock frequency of the instruction processing module 20 is fixed. For signal waveforms with different amplitude increments, the amplitude increment of the waveform data can be changed. Specifically, the shorter the pulse period, the larger the amplitude increment.

[0053] As attached Figure 3 As shown, the instruction processing module 20 includes: a status activation unit 210, which sends an output request according to the task instruction; a data conversion unit 220, which retrieves the task instruction and responds to the output request to output the corresponding waveform data; and a data judgment unit 230, which determines whether additional sampling point data is needed based on the total amount of waveform data at the rising edge and the number of waveform data output in each clock cycle.

[0054] The state activation unit 210 is normally in an idle state. Upon receiving a task instruction from the host computer, it enters a working state and sends a request to output waveform data. The data conversion unit 220 responds to the output request and outputs specific waveform data according to the waveform coefficients in the task instruction. Furthermore, a data judgment unit 230 is included to determine whether additional sampling point data is needed based on the total amount of waveform data at the rising edge and the number of waveform data output in each clock cycle. This ensures that the number of waveform data output in the last clock cycle matches the number of sampling points in each sampling cycle of the signal generation module 30, improving the integrity and accuracy of the waveform data. After the data conversion unit outputs waveform data, the state activation unit 210 is updated to an idle state until it receives the next task instruction from the host computer.

[0055] As one embodiment of this application, when the quotient of the total amount of waveform data at the rising edge and the amount of waveform data output in each clock cycle is an integer, the data judgment unit 230 determines that it is not, and directly outputs the waveform data.

[0056] As another implementation of this application, when the quotient of the total amount of waveform data at the rising edge and the amount of waveform data output in each clock cycle contains a remainder, the remainder is padded to the amount of waveform data output in each clock cycle, and the padded waveform data is output.

[0057] For example, the sampling rate of the signal generation module 30 is 1GHz, the operating clock frequency of the instruction processing module 20 is 100MHz, and the number of waveform data output per clock cycle is 10. The total number of waveform data at the rising edge of the pulse signal waveform is determined according to the amplitude increment and the initial amplitude. For example, if the initial amplitude is 0mV, the amplitude increment is 10mV, and the final amplitude is 2000mV, then the total number of waveform data at the rising edge is 200. Since the number of waveform data output per clock cycle is 10, the data conversion unit 220 can output exactly 200 waveform data in the first 20 clock cycles. At this time, no additional waveform data is needed, and the data can be output directly.

[0058] For example, if the initial amplitude is 0mV, the amplitude increment is 10mV, and the final amplitude is 2040mV, then the total number of waveform data points on the rising edge is 204. This means the data conversion unit 220 needs to output 200 waveform data points in the first 20 clock cycles and the last 4 waveform data points in the 21st clock cycle. Clearly, the waveform data output in the 21st clock cycle does not meet the requirement of 10 waveform data points, which does not match the number of sampling points in the signal generation module 30; therefore, 6 more waveform data points need to be added. The amplitude of these 6 additional waveform data points can be fixed or arbitrary, depending on the specific scenario and requirements.

[0059] In this embodiment, the control system further includes a storage module for storing the task instructions and forwarding them to the data conversion unit 220. Specifically, the host computer first stores the task instructions in the storage module. When the host computer sends a task instruction to the status activation unit 210, the data conversion unit 220 responds to the output request and retrieves the task instructions from the storage module, thus avoiding the memory occupation caused by storing the task instructions in the instruction processing module 20.

[0060] In this embodiment, the instruction processing module 20 is a functional module integrated within the FPGA. By integrating the instruction processing module 20 within the FPGA, corresponding waveform data is generated based on waveform coefficients and sent to the signal generation module 30. Furthermore, the waveform coefficients can be adjusted in real time according to control needs, outputting waveform data of various required pulse signals. Additionally, the signal generation module 30 of this application can employ a DAC unit, which is communicatively connected to the instruction processing module 20 within the FPGA, and outputs corresponding pulse waveforms based on the received waveform data.

[0061] As attached Figure 4 As shown, based on the same concept, this application also provides a method for manipulating spin qubits, used to manipulate spin qubits on a semiconductor quantum processor, specifically including the following steps:

[0062] Step S10: Receive the quantum computing task and issue the corresponding task instruction; wherein, the task instruction includes the waveform coefficients of the pulse signal.

[0063] Step S20: Generate and output waveform data of the pulse signal waveform based on the waveform coefficients.

[0064] Step S30: Output the corresponding pulse signal based on the waveform data.

[0065] Based on the same concept, embodiments of this application also provide a quantum computer, including any of the above-described spin qubit manipulation systems, or using the above-described manipulation methods to manipulate spin qubits.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0067] The above are merely preferred embodiments of this application and do not constitute any limitation on this application. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in this application without departing from the scope of the technical solutions of this application shall still fall within the protection scope of this application.

Claims

1. A spin qubit manipulation system for outputting pulse signals to manipulate spin qubits on a semiconductor quantum processor, characterized in that, include: The host computer module is used to receive quantum computing tasks and issue corresponding task instructions; wherein, the task instructions include waveform coefficients of a pulse signal, and the waveform coefficients include the initial amplitude of the rising edge of the pulse signal waveform, the amplitude increment, and the total amount of waveform data; The instruction processing module is used to generate and output waveform data of the pulse signal waveform based on the waveform coefficients. The signal generation module is used to output a corresponding pulse signal based on the waveform data.

2. The spin qubit manipulation system according to claim 1, characterized in that, The instruction processing module outputs the waveform data according to the working clock frequency.

3. The spin qubit manipulation system according to claim 2, characterized in that, The number of waveform data output by the instruction processing module per clock cycle is equal to the quotient of the sampling rate of the signal generation module and the operating clock frequency of the instruction processing module.

4. The spin qubit manipulation system according to claim 1, characterized in that, The instruction processing module includes: The status activation unit sends an output request according to the task instruction; The data conversion unit retrieves the task instruction and responds to the output request to output the corresponding waveform data; The data judgment unit determines whether additional sampling point data is needed based on the total amount of waveform data at the rising edge and the number of waveform data output in each clock cycle.

5. The spin qubit manipulation system according to claim 4, characterized in that, When the quotient of the total amount of waveform data at the rising edge and the amount of waveform data output in each clock cycle is an integer, the data judgment unit determines that it is not true and directly outputs the waveform data.

6. The spin qubit manipulation system according to claim 4, characterized in that, When the quotient of the total waveform data at the rising edge and the number of waveform data output in each clock cycle contains a remainder, the remainder is padded to the number of waveform data output in each clock cycle, and the padded waveform data is output.

7. The spin qubit manipulation system according to claim 4, characterized in that, It also includes a storage module for storing the task instructions and forwarding them to the data conversion unit.

8. The spin qubit manipulation system according to claim 1, characterized in that, The instruction processing module is a functional module integrated within the FPGA.

9. A method for manipulating spin qubits, used to manipulate spin qubits on a semiconductor quantum processor, characterized in that, include: Receive quantum computing tasks and issue corresponding task instructions; wherein, the task instructions include waveform coefficients of a pulse signal, and the waveform coefficients include the initial amplitude of the rising edge of the pulse signal waveform, the amplitude increment, and the total amount of waveform data; The waveform data of the pulse signal waveform is generated and output based on the waveform coefficients; The corresponding pulse signal is output based on the waveform data.

10. A quantum computer, characterized in that, The system includes the spin qubit manipulation system according to any one of claims 1-8, or the spin qubit manipulation method according to claim 9.

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